Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

  

MI5

noun [+ sing/pl verb]
 
 
/ˌem.aɪˈfaɪv/

Definition

the official British organization that is responsible for protecting military and political secretsSpying and espionageGovernment departments and organizations
(Definition of MI5 noun from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
Focus on the pronunciation of MI5